Implement persistent alarm storage

components/alarms/alarm_store.c

@@ -0,0 +1,77 @@
+/*
+ * SPDX-License-Identifier: AGPL-3.0-only
+ * Copyright (c) Camden Dixie O'Brien
+ */
+
+#include "alarm_store.h"
+
+#include "fatal.h"
+
+#include "esp_log.h"
+#include "esp_partition.h"
+#include "system_utils.h"
+#include <string.h>
+
+#define TAG "Alarm store"
+
+Alarm alarms[CONFIG_MAX_ALARMS];
+
+static const esp_partition_t *partition;
+
+static unsigned erase_size(void)
+{
+	unsigned sector_count = sizeof(alarms) / partition->erase_size;
+	if (sizeof(alarms) % partition->erase_size != 0)
+		++sector_count;
+	return partition->erase_size * sector_count;
+}
+
+static void load()
+{
+	const esp_err_t error
+	    = esp_partition_read(partition, 0, alarms, sizeof(alarms));
+	if (error != ESP_OK) {
+		ESP_LOGE(TAG, "Error reading from alarms partition: %02x", error);
+		FATAL();
+	}
+	unsigned count = 0;
+	for (unsigned i = 0; i < CONFIG_MAX_ALARMS; ++i) {
+		if (alarms[i].set)
+			++count;
+	}
+	ESP_LOGI(TAG, "Loaded %u alarms from storage", count);
+}
+
+void alarm_store_init()
+{
+	partition = esp_partition_find_first(
+	    ESP_PARTITION_TYPE_DATA, ESP_PARTITION_SUBTYPE_DATA_UNDEFINED,
+	    "alarms");
+	if (partition == NULL) {
+		ESP_LOGE(TAG, "Unable to find alarms partition");
+		FATAL();
+	}
+
+	if (is_first_boot()) {
+		ESP_LOGI(TAG, "Zeroing alarm store");
+		memset(alarms, 0, sizeof(alarms));
+		alarm_store_save();
+	} else {
+		load();
+	}
+}
+
+void alarm_store_save()
+{
+	esp_err_t error;
+
+	error = esp_partition_erase_range(partition, 0, erase_size());
+	if (error != ESP_OK) {
+		ESP_LOGE(TAG, "Error erasing alarm storage: %02x", error);
+		return;
+	}
+
+	error = esp_partition_write(partition, 0, alarms, sizeof(alarms));
+	if (error != ESP_OK)
+		ESP_LOGE(TAG, "Error writing alarm storage: %02x", error);
+}